Method for fitting part assemblies

Abstract

Shims used to join part assemblies are automatically designed and fabricated without the need for fitting part assemblies together in order to determine the exact dimensions of voids filled by the shims. The locations of key features on part assemblies are surveyed using a merged photogrammetry and laser tracking technique that generate the dimensions of a virtual shim. The dimensions of the virtual shim are contained in a digital file that can be used to automatically fabricate the shim using automated fabrication equipment such as a CNC machining center. The automated virtual shim design may be modified to reflect the effect of part assembly fit on performance characteristics of the aircraft.

1. A method of fitting two parts together, comprising the steps of:
 (A) measuring the location of a first set of features of a first part; 
 (B) measuring the location of a second set of features on a second part; 
 (C) generating a virtual fit between the first and second parts based on the location measurements made in steps (A) and (B); and, 
 (D) generating dimensions of shims to be positioned between the first and second parts based on the virtual fit generated in step (C). 
 
   
   
     2. The method of  claim 1 , wherein:
 step (A) includes recording the spatial locations of each of the features in the first set of features, and 
 step (B) includes recording the spatial locations of each of the features in the second set of features. 
 
   
   
     3. The method of  claim 1 , wherein steps (A) and (B) are performed using laser tracking and photogrammetry. 
   
   
     4. The method of  claim 1 , wherein at least one of steps (A) and (B) are performed by:
 generating a first set of feature position data using laser tracking, 
 generating a second set of feature position data using photogrammetry, and 
 producing a third set of feature position data by combining the first and second sets of feature position data. 
 
   
   
     5. The method of  claim 1 , wherein step (C) includes comparing the locations measured in steps (A) and (B) with a set of nominal feature locations. 
   
   
     6. The method of  claim 1 , wherein step (C) includes:
 performing a virtual nominal fit based on a set of data representing a nominal fit, and 
 optimizing the virtual nominal fit. 
 
   
   
     7. The method of  claim 1 , wherein step (C) includes:
 generating computer models of the first and second parts using the location measurements made in steps (A) and (B), and 
 comparing the computer models. 
 
   
   
     8. The method of  claim 1 , wherein step (C) is performed automatically using a programmed computer. 
   
   
     9. A method of producing shims used in fitting aircraft part assemblies together, comprising the steps of:
 (A) generating first and second sets of data respectively representing the location of features on first and second part assemblies; 
 (B) performing a virtual fit between the first and second part assemblies using the first and second sets of data; 
 (C) analyzing characteristics of the aircraft based on the virtual fit performed in step (B); 
 (D) modifying the virtual fit based on the results of step (C); 
 (E) generating the dimensions of at least one shim based on the modified virtual fit; and, 
 (F) fabricating the shim using the dimensions generated in step (E). 
 
   
   
     10. The method of  claim 9 , wherein step (A) includes measuring the locations of the features by a merged noncontact measurement process using laser tracking and photogrammetry. 
   
   
     11. The method of  claim 9 , wherein one of the part assemblies is a wing, and the characteristics analyzed in step (C) include at least one of—
 the angle of incidence of the wing, 
 the sweep angle of the wing, 
 the dihedral of the wing. 
 
   
   
     12. The method of  claim 9 , wherein the characteristics analyzed in step (C) include the attitude of at least one of the part assemblies relative to the flow of air over the aircraft. 
   
   
     13. The method of  claim 9 , wherein:
 step (E) includes generating a set of digital data representing the dimensions of the shim, and 
 step (F) includes using the set of digital data to control a machine used to fabricate the shim. 
 
   
   
     14. The method of  claim 9 , wherein step (B) includes:
 providing a set of data representing a nominal fit between the first and second part assemblies and including key geometric features of the first and second part assemblies, and 
 aligning the key geometric features of the first and second part assemblies. 
 
   
   
     15. The method of  claim 9 , wherein step (B) includes:
 aligning the features in a first set of features on the first and second part assemblies, and 
 performing a best fit between features in a second set of features on the first and second part assemblies. 
 
   
   
     16. The method of  claim 9 , further comprising the step of:
 (G) providing a set of data representing a nominal fit between the first and second part assemblies. 
 
   
   
     17. A method of manufacturing an aircraft, comprising the steps of:
 (A) manufacturing a first part assembly; 
 (B) generating a first set of data representing the position of features on the first part assembly; 
 (C) manufacturing a second part assembly; 
 (D) generating a second set of data representing the position of features on the second part assembly; 
 (E) performing a virtual fit between the first and second part assemblies using the first and second sets of data; 
 (F) generating the dimensions of shims used to fit the first and second parts assemblies together based on the virtual fit performed in step (E); 
 (G) fabricating shims based on the dimensions generated in step (F); and, 
 (H) assembling the first and second part assemblies using the shims fabricated in step (G). 
 
   
   
     18. The method of  claim 17 , wherein:
 steps (A) and (B) are performed in a first geographic location, 
 steps (C) and (D) are performed in a second geographic location, and 
 step (H) is performed in a third geographic location. 
 
   
   
     19. The method of  claim 17 , wherein steps (B) and (D) each include performing non-contact measurement of the location of the features. 
   
   
     20. The method of  claim 17 , further comprising the steps of:
 (I) analyzing characteristics of the aircraft based on the virtual fit performed in step (E); and, 
 (J) modifying the virtual fit based on the results of step (I). 
 
   
   
     21. The method of  claim 17 , wherein step (E) includes:
 providing a set of data representing a nominal fit between the first and second part assemblies, the data including key geometric features of the first and second part assemblies, and 
 aligning the key geometric features of the first and second part assemblies. 
 
   
   
     22. The method of  claim 17 , wherein step (E) includes:
 aligning the features in a first set of features on the first and second part assemblies, and 
 performing a best fit between features in a second set of features on the first and second part assemblies. 
 
   
   
     23. The method of  claim 17 , further comprising the step of:
 (I) providing a set of data representing a nominal fit between the first and second part assemblies. 
 
   
   
     24. A method of manufacturing an aircraft, comprising the steps of:
 (A) fabricating a first part assembly in a first manufacturing process; 
 (B) generating a first set of data representing the position of features on the first part assembly; 
 (C) fabricating a second part assembly in a second manufacturing process; 
 (D) generating a second set of data representing the position of features on the second part assembly; 
 (E) performing a virtual fit between the first and second part assemblies using the first and second sets of data; 
 (F) analyzing characteristics of the aircraft based on the virtual fit performed in step (E); 
 (G) modifying the virtual fit based on the results of step (F); and, 
 (H) altering at least one of the first and second manufacturing processes based on the results of the modified virtual fit. 
 
   
   
     25. The method of  claim 24 , wherein:
 steps (A) and (B) are performed in a first geographic location, and, 
 steps (C) and (D) are performed in a second geographic location. 
 
   
   
     26. The method of  claim 25 , further comprising the step of:
 (I) assembling the first and second part assemblies in a third geographic location. 
 
   
   
     27. The method of  claim 24 , wherein steps (B) and (D) each include performing non-contact measurement of the location of the features. 
   
   
     28. The method of  claim 24 , further comprising the steps of:
 (I) analyzing characteristics of the aircraft based on the virtual fit performed in step (E); and, 
 (J) modifying the virtual fit based on the results of step (I). 
 
   
   
     29. The method of  claim 24 , wherein step (E) includes:
 providing a set of data representing a nominal fit between the first and second part assemblies, the data including key geometric features of the first and second part assemblies, and 
 aligning the key geometric features of the first and second part assemblies. 
 
   
   
     30. The method of  claim 24 , wherein step (E) includes:
 aligning the features in a first set of features on the first and second part assemblies, and 
 performing a best fit between features in a second set of features on the first and second part assemblies.